Nonrigid airship



' 1,682,405 H. NAATZ NONRIGID AIRSHIP Filed March 30,. 1925 PatentedAug. 28, 1928.

UNITED STATES PATENT orr-lcs.

KIRHANN NAA'I'Z, OF BERLIN-OHABLOTTENBURG, GERMANY, ASSIGNOB, BY HESNEASSIGNMENTS, TO FIRM LUIT-FAHRZEUG GESELLSCHAFT M. B. E, OF KLEISTSTB.,BERLIN, GERMANY, A CORPORATION OF GERMANY.

NON RIGID AIBSHIP.

Application filed larch-30, 1923, Serial No. 628,851, and in GermanyApril 13, 1922.

This invention relates in general to airships and more particularly toairships of the non-rigid type. It is well known that the most importantpart of air-ships of the nonrigid type is the envelope, for this is thepart that receives the gas charge and that has to resist the pressuresproduced thereby and also the external forces which are liable to arisewhen the load is unevenly distributed and when the ship passes throughsqualls and is steered by its rudder etc. The pressure of the gas in theenvelope only gives rise to tensional stresses, while the externalforces produce both tensional and pressure or thrust stresses, whichgenerally spread in accordance with know laws over the surface of theenvelope and are superimposed upon the stresses due to'the gas pressurein the envelope, so that at some parts of the envelope the tensionalstresses are increased while at others they are reduced. Consequentlythe envelope is not stretched equally at all points, and the stretchingof the envelope is notsymmetrical at all parts, so that the'body of theballoon is deformed, or in other words it is subjected to thrust,bending and torsional stresses. As the envelope of a non-rigid airshipis made of material such as fabric which is very easily deformed thesethrust, bending and torsional stresses may-often be very considerable,and the may become so great that the steerability o the ship isinterfered withand on the other hand the structures, such as the gangwaysuspended from the body of the ship, are unduly pressed, pulled or bent.To avoid these undue stresses of the suspended structures the have to bemade, in airshi s of the knownk into one another like telescopes, or ofextreme.- ly strong parts. If the latter course is adopted, thesuspended structure revents deformation of the balloon b sti ening it,but it then has to be ca able 0 resisting very great stresses. This p anis utilized in ships of the semi-rigid type. But the construction. ofstifiening structures or members of this kind involves at difiiculties,because it is not certain M at part of the external forces is coped withby the balloon and what part is received by the stiff structure, becausethe exansional properties of the material of the alloon are uiteirregular and differ from those of meta to such an extent (wovenmaterial stretches 150 times as much as aluminind, either of parts thatsli e ium) that no rules regardim the distribution of the forces can befoun 1 These disadvantages of non-rigid and semirigid airships areavoided by the present invention. In accordance with this invention theenvelope is made so as to be defprmable to aslight extent only, and thisis accomplished by making the envelope of three separate parts, one ofwhich is constructed of members which are substantially non-expansiblesuch as wire ropes, wire cords, wires, rods and the like. The'part thatconsists of practically non-expansible members is made in the form of anetwork which covers or embraces an interior gas-filled envelope andwhich is surrounded by a second outer airtight envelope. The inventionis shown by way of example in the drawing in which Fig. 1 is adiagrammatic side elevation with a part of the external envelope brokenaway to show the network covering.

Fig. 2 is a diagrammatic section of the airship. i

Fig. 3 is a cross section of an airship with a ballonet arranged insidethe internal envelope 'for keeping the envelope taut,

F 1g. 4 is a modification in which a ballonet is arranged outside of'theinterior envelope,

and

Fi 5 is another modification in which the interior of the, ship isdivided by a vertical partition.

The three parts of the envelope are arranged as follows: Referring tothe drawing a is a network cover which embraces or surrounds a gastightenvelope 6. The network a consists of substantially non-expansiblemembers, the transverse and diagonal members being tension members,while the longitudinal members may be subjected either to tension orthrust, or both. The envelo e 1) consists of a gastight, flexiblematerial w ich presses against the network a. The network a is coatedexternally by an envelo e c which is also made of a flexible materiawhich is airtight but need not be as tight as the en-- 'the suspendedstructure.

construction the two envelopes b and 'c of fabric or flexible materialare subjected to small tensional stress and nearly the Whole of thetensional stresses, which is ordinarily taken by the envelope ofairships of the nonrigid type, is taken in the airship according to mylnvention by the network a alone. As this network consists of memberswhich are practically non-elastic and which extend transversely,diagonally and longitudinally as shown in Fig. 1, the body of theballoon will only be deformed very little by the influence of allexternal forces that may arise. The thrust or pushing together, bending,and torsion of the body of the balloon will he so slight that itssteerability will not be impaired and structures connected to it, whichserve to take the loads to be carried, will be stretched, compressed orbent very little, or not at all. Hence these structures can be made muchlighter than in non-rigid airships equipped with elastic envelopes only.

In a particularly advantageous construction, the suspended structuresare made of separate pieces f asshown in Fig. 1 interconnected bymovable joints 9 suspended from the balloon in such a manner that thejoints 9 all lie in a curved surface AB that adapts itself to thecontour of the balloon. The suspended structure will then exerttensional or pressure stresses on the network covering of the balloon inthe surface AB only, and its parts that lie beneath the surface AB canthen be made as light as possible. The balloon may be deformed, as bybending, very considerably without affecting the parts of Besides, if itis considered necessary to increase the resistance to bending stresses,this can be accomplished by simply strengthening the upper booms of thesuspended structure that lie in the surface A-B.

The body of the balloon may he constructed in various ways. In Fig. 3the envelope 6 in the interior of the carrier network a consists of agastight balloon b of fabric or the like andin the envelope 1) there isa ballonet h, and the surrounding chamber M is filled with air oranother gas. The surrounding chamber M may be connected with theinterior of the ballonet C or these two chambers C and- M may bearranged to have air pumped into them separately by a blower. In Fig. 4the inner envelope is divided up into a number of separate cells I) andthe bottom of the balloon is closed by a covering 2'. Here also theouter chamber M may be connected to the air chamher D containing air atthe service pressure as shown in the drawing, or the chambers D and Mmay be separated by the covering 2' being made to extend further up intothe halloon. In Fig. 5 an airship is shown in which a vertical partition6 divides the interior of the body of the balloon into two longitudinalchambers. The partition e may consist of fabric or of network made ofsubstantially non-expansible members such as metal rope, metal strandsor the like, the object of the partition e being to hold down the top ofthe balloon. By providing the partition no substantial change of theconstruction of the envelopes is necessary as these may be inserted inthe manner shown in Figs. 3 4 or 5. If desired, several partitions e mayhe provided.

The external chamber M, Figs. 2, 3 and 5, besides providing a smoothenclosing external surface, also offers the advantage that it preventsrapid heating of the gases by the sun, for experience has shown that gasenclosed in balloons provided with only a single envelope heats up muchquicker. This heating of the gas is delayed to a still greater extent orprevented alto ether when the air in external chamber M is keptcontinually in motion, which may be done by pum ing in fresh air frombeneath and allowing the heated air to escape at the top throughadjustable valves.

Another important advantage obtained by the network cover according tothe invention consists in the factthat, in the event of individualmembers of the network being severed, the network cover does notcontinue tearing like the fabric of ordinary non-rigid airshipsgenerally does, because, if meshes of suitable width are chosen, only afew tension members will be torn asunder and the forces that wereresisted by them are immediately transferred to neighboring memberswhich then take the strain without being damaged, since the extra loaddoes not subject them to more than double the ordinary stress, and theyare generally calculated to take three times the normal stress.

I claim 1. In an airship of the non-rigid type, a gas-containingenvelope, a network embracmg said envelope for preventing deformation ofsame and consisting of longitudinal, diagonal and transversenon-expansible flexible members whose sections are interconnected so asto make the body of the ship pliable in all directions, an outerenvelope over the network and a structure suspended from the networkcovering and comprising members connected to each other by movablejoints that lie in a curved surface beneath said envelopes.

2. In an airship of the non-rigid ty e, a gas containing envelope, 9.network em racmg said envelope for preventing deformation of same andconsisting of longitudinal, dia onal and transverse non-egpansihle fiexi1e members whose sections are interconnected so as to make the body ofthe ship pliable in all directions, an outer envelope over the network,and a structure suspended from the network covering.

In testimony whereof I aflix my signature.

' HERMANN NAATZ.

